Miniaturization and diversification of semiconductor devices have progressed more and more, and a processing method thereof covers a wide range with respect to each of device structures and production steps. As regards etching of the substrate, development of both dry etching and wet etching has been advanced, and a variety of chemical liquids and processing conditions have been proposed depending on kinds and structures of the substrate material.
Above all, when a high-integrated device structure is produced, a technique of etching a prescribed material precisely is important and as one of techniques of addressing such problem, a wet etching which utilizes a chemical liquid is exemplified. For example, a precise etching processing is required in the production of circuit wiring of a microscopic transistor circuit, a metal electrode material, or a substrate having a barrier layer, a hard mask, and the like. However, sufficient study has not yet been done on etching conditions and chemical liquids suitable for each of the substrates containing a wide variety of metal compounds. Under these circumstances, efficient removal of a hard mask or the like applied to the device substrate has been laid out as a production problem. Specifically, as regards titanium nitride (TiN) which is applied as a metal hard mask, there are several examples of studies on chemical liquids for etching this material (see Patent Literatures 1 to 6).